With the pilot for Jane Goldman‘s Game of Thrones prequel series set to film in February, casting on the project has begun to come together. Last week it was announced that Naomi Watts and Josh Whitehouse has joined the project. Like Game of Thrones, the prequel (which author George R. R. Martin has referred to as The Long Night) will feature over a dozen lead actors as the story of Westeros’ descent into darkness unfolds. Goldman and casting director Lucinda Syson have their work cut out for them over the next several weeks as they attempt to round out the cast, but they have set their sights on two more actors to fill key roles: Sheila Atim and Denise Gough.

Atim, who starred in director Adam Smethurst’s adaptation of Shakespeare’s Twelfth Night, is an Olivier Award winning stage actress and is a rising star in London’s theatrical community. Should she sign on, Atim’s role would be one of at least 6 lead roles meant to be filled by people of color. Actress Letitia Wright (Black Panther) was offered one of those roles (separate from Atim’s) but did not agree to terms with the studio.

The Irish-born Gough, who recently starred in the UK thriller Steel Country, would be filling what we are told is a critical role in the series though no further details were revealed.

Neither actress had officially joined the series at the time of publication though both were said to be in negotiations. The pilot will film in February and March with the rest of the series expected to begin production beginning in July.